Method of mounting a Kelly bar on a drilling machine, relevant mounting tool and a drilling machine equipped with such mounting tool

Abstract

A method of mounting a kelly bar on a drilling machine includes a step of installing a mounting tool between the rod of a pull-down cylinder and a rotary carriage of the drilling machine. Once the mounting tool has been installed, the drilling machine can be set up with a kelly bar that is longer than the usual kelly bars.

The invention claimed is: 
     
       1. A method of mounting a kelly bar on a drilling machine, the method comprising:
 setting a pull-down cylinder containing a rod in an extended condition to bring a rotary carriage and a drilling rotary to a distance H or to a position close to the distance on a guide tower; 
 locking the rotary carriage on the guide tower; 
 disengaging the rotary carriage from the pull-down cylinder; 
 switching the pull-down cylinder from the extended condition to a retracted condition by an extent at least equal to a length of a mounting tool provided with at least one traction element; 
 installing the mounting tool between the rod of the pull-down cylinder and the rotary carriage; 
 unlocking the rotary carriage on the guide tower; 
 switching the pull-down cylinder to the extended condition to bring the drilling rotary to a distance H 1  greater than the distance H; 
 connecting a rope to the kelly bar; 
 lifting the kelly bar by operating a main winch of the drilling machine, up to bring a lower end of the kelly bar above the drilling rotary; 
 aligning the kelly bar with an annular passage of a drive sleeve of the drilling rotary; 
 retracting the rod of the pull-down cylinder to obtain a rise of the rotary carriage and the drilling rotary up to a point, which has a distance from a head of the guide tower that is equal to or less than the distance H, the retraction of the rod of the pull-down cylinder determining a sliding engagement of the annular passage of the drive sleeve of the drilling rotary to the kelly bar; 
 locking the rotary carriage on the guide tower; 
 disassembling the mounting tool by disengaging the at least one traction element between the rod of the pull-down cylinder and the rotary carriage; 
 switching the pull-down cylinder in to the extended condition; 
 connecting the rod of the pull-down cylinder to the rotary carriage; and 
 unlocking the rotary carriage on the guide tower, 
 wherein 
 the head of the guide tower is provided with at least one pulley for the rope from the main winch of the drilling machine to engage one end of the kelly bar, directly or indirectly, through a rotatable element, to move the kelly bar; 
 the drilling rotary is slidingly engaged to the guide tower through the rotary carriage and has the driving sleeve with the annular passage for inserting and engaging the kelly bar; 
 the pull-down cylinder is engaged to the guide tower; 
 the pull-down cylinder is engaged to the rotary carriage and the drilling rotary via the rod of the pull-down cylinder to move the rotary carriage and the drilling rotary along the guide tower; 
 the retracted condition is a condition in which the rod of the pull-down cylinder is disposed within the pull-down cylinder; 
 the extended condition is a condition in which the rod of the pull-down cylinder is disposed outside the pull-down cylinder; and 
 the distance H is defined by a maximum downward sliding of the rotary carriage controlled by the rod of the pull-down cylinder in the extended condition. 
 
     
     
       2. The method according to  claim 1 , further comprising:
 before connecting the rope to the kelly bar, carrying out a forward inclination of the guide towel; and 
 before or simultaneously with aligning the kelly bar to the annular passage of the drive sleeve of the drilling rotary, straightening the guide tower to a vertical direction. 
 
     
     
       3. The method according to  claim 1 , further comprising:
 before retracting the rod of the pull-down cylinder to return the drilling rotary to the distance H, moving the kelly bar, by unwinding the rope to lead the kelly bar to cross the annular passage of the drive sleeve of the drilling rotary. 
 
     
     
       4. The method according to  claim 1 , wherein:
 at least one of said locking the rotary carriage on the guide tower includes installing one or more stop pads on guides of the guide tower; and 
 at least one of said unlocking the rotary carriage on the guide tower comprises disassembling the one or more stop pads from the guides of the guide tower. 
 
     
     
       5. The method according to  claim 1 , wherein said installing the mounting tool between the rod of the pull-down cylinder and the rotary carriage includes:
 connecting one end of a rigid traction element of the mounting tool to the rod of the pull-down cylinder using at least one pin; and 
 connecting the other end of the rigid traction element of the rigid mounting tool to the rotary carriage using at least one pin. 
 
     
     
       6. The method according to  claim 1 , wherein said installing the mounting tool between the rod of the pull-down cylinder and the rotary carriage includes:
 connecting one end of a first flexible traction element of the mounting tool to the rotary carriage using at least one pin; 
 connecting another end of the first flexible traction element of the mounting tool to one end of a second rigid traction member of the mounting tool using at least one pin; and 
 connecting another end of the second rigid traction element of the mounting tool to one end of the rod of the pull-down cylinder using at least one pin. 
 
     
     
       7. The method according to  claim 6 , further comprising:
 after said installing the mounting tool and before said unlocking the drilling rotary, adjusting the pull-down cylinder so that the pull-down cylinder is in the retracted condition of a measure sufficient to put under tension the first flexible traction element of the mounting tool. 
 
     
     
       8. A drilling machine, comprising:
 a guide tower equipped with a head provided with at least one pulley; 
 a main winch equipped with a rope to engage, directly or indirectly, through a rotating element, one end of a kelly bar to move the kelly bar; 
 a drilling rotary slidingly engaged to the guide tower via a rotary carriage and having a driving sleeve having an annular passage for inserting and engaging the kelly bar; 
 a pull-down cylinder, wherein the pull-down cylinder is engaged to the guide towel, the pull-down cylinder has a rod and is engageable to the rotary carriage and the drilling rotary via the rod to move the rotary carriage and the drilling rotary along the guide tower, the pull-down cylinder switches between a retracted condition in which the rod is provided inside the pull-down cylinder and an extended condition in which the rod is provided outside the pull-down cylinder, and the pull-down cylinder defines, in the extended condition, a distance H of maximum downward sliding of the rotary carriage; and 
 a mounting tool for mounting the kelly bar on the drilling machine, wherein the mounting tool contains at least one traction element installable between the rod of the pull-down cylinder and the rotary carriage of the drilling machine and is installed between the rod of the pull-down cylinder and the rotary carriage.